Abstract

We present an experimental study on terahertz (THz) magneto-optical (MO) properties of tri-layer graphene on quartz substrate, grown by chemical vapor deposition. The MO conductivities are measured in the Faraday geometry by applying optical polarization and using THz time domain spectroscopy (TDS) in high magnetic fields at liquid nitrogen temperature. We find that the real and imaginary parts of the longitudinal and transverse MO conductivities fit well to the classic MO Drude formula for tri-layer graphene. Thus, we are able to determine optically the key sample parameters such as the electron density, the electron effective mass and the relaxation time for tri-layer graphene. The dependence of the relaxation time on magnetic field is examined. This work indicates that THz TDS can be employed as a powerful tool to measure MO properties of tri-layer graphene and other 2D electronic materials in the presence of high magnetic fields.

摘要

我们目前对通过化学气相沉积法生长的石英衬底上的三层石墨烯的太赫兹（THz）磁光（MO）特性进行实验研究。通过在液氮温度下的强磁场中施加光偏振并使用THz时域光谱法（TDS），在法拉第几何中测量MO电导率。我们发现纵向和横向MO电导率的实部和虚部都非常适合用于三层石墨烯的经典MO Drude公式。因此，我们能够从光学上确定关键样品参数，例如三层石墨烯的电子密度，电子有效质量和弛豫时间。检查了弛豫时间对磁场的依赖性。